On source selection and frame stability

S. B. Lambert and A.-M. Gontier

Systèmes de Référence Temps Espace, Observatoire de Paris, France

Poster

We explore several selection algorithms that allows one to rank radio sources following their ability to be part of a celestial reference frame significantly more accurate than the current ICRF. We compare two methods. The first one considers sources individually through their positional time stability: the frame is based on a selection of the most 'stable' sources. We show that the frame stability is improved with respect to the ICRF defining set by a factor of 2. In the second method, the algorithm builds the frame by searching directly for the sources that minimize the axis time variability, without any constraint on sources' own positional stability. The latter method appears to be very sensitive to the way the source coordinate time series are derived and is currently unable to provide a large set of defining sources.